Vitamin K plays a key role in helping the blood clot, preventing excessive bleeding. Unlike many other vitamins, vitamin K is not typically used as a dietary supplement. Vitamin K is actually a group of compounds. The most important of these compounds appears to be vitamin K1 and vitamin K2. Vitamin K1 is obtained from leafy greens and some other vegetables. Vitamin K2 is a group of compounds largely obtained from meats, cheeses, and eggs, and synthesized by bacteria. Why do people take vitamin K? Low levels of vitamin K can raise the risk of uncontrolled bleeding. While vitamin K deficiencies are rare in adults, they are very common in newborn infants. Vitamin K is also used to counteract an overdose of the blood thinner Coumadin. While vitamin K deficiencies are uncommon, you may be at higher risk if you: Have a disease that affects absorption in the digestive tract, such as Crohn's disease or active celiac disease Take drugs that interfere with vitamin K absorption Are severely malnourished Drink alcohol heavily Good natural food sources of vitamin K include Vegetables like spinach, asparagus, and broccoli, Beans and soybeans, Eggs, Strawberries and Meat Most people get enough K from their diets to maintain adequate blood clotting, but NOT enough to offer protection against the following health problems: Arterial calcification, cardiovascular disease, and varicose veins Osteoporosis Prostate cancer, lung cancer, liver cancer, and leukemia Brain health problems, including dementia Vitamin K comes in two forms, and it is important to understand the differences between them before devising your nutritional plan of attack. The Two Basic Types of Vitamin K. Vitamin K can be classified as either K1 or K2: Vitamin K1: Found in green vegetables, K1 goes directly to your liver and helps you maintain a healthy blood clotting system. (This is the kind of K that infants need to help prevent a serious bleeding disorder.) It is also vitamin K1 that keeps your own blood vessels from calcifying and helps your bones retain calcium and develop the right crystalline structure. Vitamin K2: Bacteria produce this type of vitamin K. It is present in high quantities in your gut, but unfortunately is not absorbed from there and passes out in your stool. K2 goes straight to vessel walls, bones, and tissues other than your liver. MK-4 is a synthetic product, very similar to vitamin K1, and your body is capable of converting K1 into MK-4. However, MK-4 has a very short half-life of about one hour, making it a poor candidate as a dietary supplement. After reaching your intestines, it remains mostly in your liver, where it is useful in synthesizing blood-clotting factors. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.